Improvement in elastic graduated scale



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IMPROVEMENT IN ELASTIC GRADUATED SCALE.'

The Sbhedule referred to in these Lettori Patent and making part of the ma I, RICHARD MEADE BAcrrE, of Philadelphia, county of Philadelphia., State of Pennsylvania, have inventedl an Elastic Scale, of which thc following is a specification.

Nature and Objectqof the Invention. `lirIyinvention consists of an elastic graduated scale,

composed of a number of strands of caoutchouc united ubstautially in thc manner hereinafter described, sol

that when stretched the graduatious of the scale are,

l for practical purposes, uniform throughout, and bear to each other the same relation as they do when parjtially or wholly relaxed, thereby rendering the scale serviceable in various useful arts and manufactures.

Description of the Accompanying Dfrauf'r'rrg.

I have discovered that the fabric known .as elastic rubber braid, or elastic webbing or tapc,possesses the property of stretching and relaxing uniformly, or very nearly so, throughout, and, therefore, is especially applicabie to scales requiring the quality of proportional 'extension and contraction.

If, for instance, a piece of elastic braid, say an eighth of an inch wide and six inches long, composed of, sa'y, six strandsof caoutchouc, asshown in tig. 1, be marked with graduation, say, at intervals of a. quarter of au inch, and bestretched-to the extent of half its length, it will be found that the graduaticns have become tlrrcc-eighths of an inch apart, orr in other words, the braid has str-etched uniformly throughout, and, if the said braid be still farther stretched or be relaxed, it will be found to work uniformly.

This uniformity in the stretching and relaxing of the fabric I ascribe to the fact that it is composed of a uurnber of strands of caoutchouc inclosed by a web of silk, cotton, or linen threads@ Although the material of the strands nnot be perfectlyhomogeneous, nor any two of them identical in sizc or form, yet, by tbc principle ot' compensation, the `imperfections of one strand practically' counteract those of thc other, and hence the'str nkds, when united, are in the aggregate uniform, andpdssess 'the capability of equal, or nearly equal,"propovr tioiral extension and contraction at all points.

' The uniformity of thc graduatious when the braid is stretched or relaxed, depends, in a. measure, upon the quality of the manufacture.'

In experimenting for elasticscalcsfor the use of tailors, 1 have found that thc requisite accuracy can be obtained with'an elastic tape thrcc-cighths of an inch wide.

In making an elastic scale for plotting the work of that branch of surveying kuowrr ashydrograplry, (and I have applied my invention to it with succcss,) I use a tiner material than that' just mentioned, consisting of a. flat braid about an eight of an inch wide and composed ,ofsix strands inc-loscd in a web of tineI thread. r r

I have presented in thc accompanying illustration thedrawirrg of an instrument devised for aid in applying my invention to hydrography.

Near each cud of a flat strip, A, of well-seasoned wood, is secured a standard, a, from which prdiccts a spindle, B, and on the lattcr a' drum, b, is arranged to rcvolve freely, one tiange c of this drurn being milled on the edge so as to facilitate its manipulations, and the other flange being ratcheted so as to receive thc pawlloosely hung on the standard u.. As thc ends of this instrument are alike, it has not been deemed rre- ,ccssaryto exhibit in the drawing more than one cud.

One end of t-lre graduated elastic sca-le is attached to the drnmat onc end of the instrument, and the other end tothe drum at the opposite end of the instrument, the intermediate part passing downward from the drums and around pins projecting from the edge of thc strip A, so that, when thc scale is applied to a map, it shall be'iu contact, orvcrv nearly` in contact, therewith.

By manipulating thc milled flanges c of either of the drums, the elastic scale can by stretching, or relaxing it, bc adjusted to any desir-ed position.

Those/dro are familiar with hydrograplry, will, from the preceding explanation, readily understand the rrrodc of applying rny invention to the plotting of soundings.

I'wish-it to be understood, however, thatin exhibiting the drawing of an instrumentfor applying my invention to a certain use, I have no intention to here vclaim that or any other instrument, as thc method of applying my invention.will depend in a great -rncasure yon theartor manufacture to which ithas to be adapted,

and in' many cases my elastic scale may be employed without the. :rid of any instrument whatever'.

I have alluded to the aid which my invention will render to tailors or cutters' of garments, and to hydrographcrs, but it rnust be evident that its application is not limited to them, but may be extended to various artisans and manufacturers.

Claim.

A graduated bs-aid, webbing or' tape, composed of a number of strands of caoutchouc united substantially` in the maner hercinbetbre described.

In testimony whereof I have signed my namc to this specification in the presence of two subscribing witnesses.

RICHARD MFDE liACllli.

Witnesses a 

